From 54a6ba09c66d680b027c66c6219bdd06df02ed75 Mon Sep 17 00:00:00 2001
From: Looly <loolly@gmail.com>
Date: Wed, 26 Jan 2022 18:35:16 +0800
Subject: [PATCH] fix cv

---
 CHANGELOG.md                                  |  1 +
 .../cn/hutool/core/text/csv/CsvWriter.java    | 29 ++++++++++++-------
 .../hutool/core/text/csv/CsvWriterTest.java   |  3 +-
 .../hutool/extra/qrcode/QrCodeUtilTest.java   |  2 ++
 4 files changed, 24 insertions(+), 11 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e53326887..470e96df7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,7 @@
 * 【db     】     新增条件组，用于处理复杂的where条件（pr#514@Gitee）
 * 【core   】     新增LocalDateTimeUtil.weekOfYear（issue#I4RWXC@Gitee）
 * 【core   】     Month增加toJdkMonth、getValueBaseOne
+* 【core   】     CsvWriter修改规则，去除末尾多余换行符（issue#I4RSQY@Gitee）
 
 ### 🐞Bug修复
 * 【core   】     修复ChineseDate农历获取正月出现数组越界BUG（issue#2112@Github）
diff --git a/hutool-core/src/main/java/cn/hutool/core/text/csv/CsvWriter.java b/hutool-core/src/main/java/cn/hutool/core/text/csv/CsvWriter.java
index 878011082..5c386214e 100644
--- a/hutool-core/src/main/java/cn/hutool/core/text/csv/CsvWriter.java
+++ b/hutool-core/src/main/java/cn/hutool/core/text/csv/CsvWriter.java
@@ -1,6 +1,7 @@
 package cn.hutool.core.text.csv;
 
 import cn.hutool.core.bean.BeanUtil;
+import cn.hutool.core.collection.ArrayIter;
 import cn.hutool.core.collection.CollUtil;
 import cn.hutool.core.convert.Convert;
 import cn.hutool.core.io.FileUtil;
@@ -45,6 +46,10 @@ public final class CsvWriter implements Closeable, Flushable, Serializable {
 	 * 是否处于新行开始
 	 */
 	private boolean newline = true;
+	/**
+	 * 是否首行，即CSV开始的位置，当初始化时默认为true，一旦写入内容，为false
+	 */
+	private boolean isFirstLine = true;
 
 	// --------------------------------------------------------------------------------------------------- Constructor start
 
@@ -183,13 +188,7 @@ public final class CsvWriter implements Closeable, Flushable, Serializable {
 	 * @throws IORuntimeException IO异常
 	 */
 	public CsvWriter write(String[]... lines) throws IORuntimeException {
-		if (ArrayUtil.isNotEmpty(lines)) {
-			for (final String[] values : lines) {
-				appendLine(values);
-			}
-			flush();
-		}
-		return this;
+		return write(new ArrayIter<>(lines));
 	}
 
 	/**
@@ -320,9 +319,14 @@ public final class CsvWriter implements Closeable, Flushable, Serializable {
 	public CsvWriter writeComment(String comment) {
 		Assert.notNull(this.config.commentCharacter, "Comment is disable!");
 		try {
+			if(isFirstLine){
+				// 首行不补换行符
+				isFirstLine = false;
+			}else {
+				writer.write(config.lineDelimiter);
+			}
 			writer.write(this.config.commentCharacter);
 			writer.write(comment);
-			writer.write(config.lineDelimiter);
 			newline = true;
 		} catch (IOException e) {
 			throw new IORuntimeException(e);
@@ -366,12 +370,17 @@ public final class CsvWriter implements Closeable, Flushable, Serializable {
 	 * @param fields 字段列表 ({@code null} 值会被做为空值追加)
 	 * @throws IOException IO异常
 	 */
-	private void doAppendLine(final String... fields) throws IOException {
+	private void doAppendLine(String... fields) throws IOException {
 		if (null != fields) {
+			if(isFirstLine){
+				// 首行不补换行符
+				isFirstLine = false;
+			}else {
+				writer.write(config.lineDelimiter);
+			}
 			for (String field : fields) {
 				appendField(field);
 			}
-			writer.write(config.lineDelimiter);
 			newline = true;
 		}
 	}
diff --git a/hutool-core/src/test/java/cn/hutool/core/text/csv/CsvWriterTest.java b/hutool-core/src/test/java/cn/hutool/core/text/csv/CsvWriterTest.java
index 18203196c..0564af9ac 100644
--- a/hutool-core/src/test/java/cn/hutool/core/text/csv/CsvWriterTest.java
+++ b/hutool-core/src/test/java/cn/hutool/core/text/csv/CsvWriterTest.java
@@ -2,7 +2,6 @@ package cn.hutool.core.text.csv;
 
 import cn.hutool.core.io.FileUtil;
 import cn.hutool.core.util.CharsetUtil;
-import org.junit.Ignore;
 import org.junit.Test;
 
 public class CsvWriterTest {
@@ -19,6 +18,8 @@ public class CsvWriterTest {
 				CharsetUtil.CHARSET_GBK, false, csvWriteConfig);
 
 		writer.writeHeaderLine("name", "gender", "address");
+		writer.writeLine("张三", "男", "XX市XX区");
+		writer.writeLine("李四", "男", "XX市XX区,01号");
 		writer.close();
 	}
 }
diff --git a/hutool-extra/src/test/java/cn/hutool/extra/qrcode/QrCodeUtilTest.java b/hutool-extra/src/test/java/cn/hutool/extra/qrcode/QrCodeUtilTest.java
index 7f31d796f..30dde68d6 100644
--- a/hutool-extra/src/test/java/cn/hutool/extra/qrcode/QrCodeUtilTest.java
+++ b/hutool-extra/src/test/java/cn/hutool/extra/qrcode/QrCodeUtilTest.java
@@ -94,4 +94,6 @@ public class QrCodeUtilTest {
 		final BufferedImage image = QrCodeUtil.generate("content111", BarcodeFormat.PDF_417, QrConfig.create());
 		Assert.assertNotNull(image);
 	}
+
+
 }